Lubricating oil composition



Patented Apr". 19, r i V UNITED STATES PATENT OFFICE LUBRICATIN G OIL COMPOSITION Franklin M. Watkins, Chicago, Ill., assignor to Sinclair Rcflning Company, New York, N. Y., a corporation of Maine No Drawing. Application November 28, 1944, Serial No. 565,569

I 4 Claims. (Cl. 252-4237) 2 This invention relates to lubricating oil comwherein Y is either aromatic or aliphatic or a positions and more particularly to lubricating oil mixture of such sulfides prepared from a mixture compositions, consisting principally of a petroof mercaptans of five carbon atoms per molecule leum lubricating oil fraction, with which there such as that extracted from gasoline.

has been compounded a calcium organic com- 5 Amino olefin sulfides, i. e., whereYof the forepound and an olefin sulfide, and having improved going structural formula is NRFR where R.

characteristics especially with respect to oxidation may be hydrogen or aromatic or aliphatic hydroand corrosion. carbon. For instance, diamyl olefin dlsulfide, i. e.,

It has previously been recognized that oxidawhere each R is an amyl group, and anilino olefin tion of many petroleum lubricating oil c'omposi- 1t disulfide, where one RF is hydrogen and the other tions is materially accelerated by contact with is CeHs, may be used with particular advantage. certain bearing metals or alloys, notably copper- These olefin sulfides have in common the charlead alloys. It has also been recognized that the actcristic that at least one and usually two adjapresence of various metallo-organic substances, cent carbon atoms of each original olefin molecule included in the oil composition, for improving 1 is substituted by an electrcnegative sulfur atom. the characteristics of the lubricant in various This type of substitution ap to serve to actirespects, may ultimately detrimentallyafiect oxivate the carbon-sulfur bonds thereby changing dation and corrosion characteristics of the lubri-- their normal reactions. Further, these sulfides cant. Copper-lead-alloys, for example, are known have been found to be soluble in lubricating oil materially to catalyze the oxidation of the oil. fractions in effective amounts and to be compatible Various metal compounds, notably calcium organic with conventional detergents. compounds, for instance the calcium salt of octyl The olefin sulfides used in accordance with my salicylates, used in lubricating oil compositions present invention may be prepared by reacting as detergents and oxidation inhibitors, have been an olefin or a mixture of olefins boiling in the found actually to effect an increase over the nor- 2. gasoline range with either sulfur dichloride, SCI-i,

' mal rate of corrosion of copper-lead bearing alloys or sulfur monochloride, S2012, by known methods by the lubricant and the normal rate of oxidation to introduce sulfur and chlorine at the double of the lubricating oil composition at the terminabonds, in accordance with the formula tion of the induction period.

I have discovered that the corrosion and oxida- ZRCILCHR CH 01mm tion characteristics of lubricating oil compositions I 1 in the p e of p d t et Such and thereafter treating the product of the reacdeter e t ate a s may be su sta tia y mtion with an alkali metal sulfide, mercaptide or proved by the inclusion therein of relatively small in compo nd t replace the chlorine, as more proportions of certain olefin sulfides, the detri- 3- fully h r inafter described. mental activity of the metal and metallo-organic v ri olefins o lefin mixtures may be used materials present being thereby substantially i th preparation of my olefin sulfides. It is inhibited- Also. when used n larger p po tio s, desirable to use olefins or mixtures of olefins these sulfides have been found favorably to affect having a boiling range within that of cracked the film strength of the composition. a 44 naphtha, say 200 t 300 F, However, some olefins The Ol fi Sulfide, used n accordance with my lend themselves more readily than others to the pre t invention. may be ep e ted by the preparation of the olefin sulfides of my present Structural formula! invention. Upon sulfo-chlorination, some olefins I V have a stronger tendency thanothers to lose the R R R R. I V R L 45 chlorine as hydrochloric acid. Accordingly, the I I I w substitution of other radicals for the chlorine of Y R R Y the sulfo-chlorinated olefin is more difficult with wherein R is' hydrogen or a hydrocarbon radical, such olefins and the product of the reaction less S is sulfur, x is either 1 or 2 and Y is aradical stable. selected from the group consisting of SH,-SR The olefin mixtures resulting from thermal and'a mino radicals, the R representing a-hydrocracking are available at low cost and in adecarbon radical. quate quantities and may be used in the prep- Examples of my improved addends which have aration of my olefin sulfides. .However, this been used with particular advantage include: thermally cracked product frequently consists Mercapto olefin sulfides, i. e., where Y' of the largely oftertiary olefins, i.e., unsymmetrically above structural formula is SR, R being either di-alkylated ethylene or tri-substituted ethylene. a hydrogen atom or a hydrocarbon radical. These tertiary olefins form, on sulfo-chlorination, Mercapto olefin disulfides, i. e., where a: is 2 and tertiary chlorides which lose HCl rather readily Y is SH, have been found particularly effective. during sulfo-chlorination and subsequent treat- Suitable mercapto olefin sulfides-include those ment in the preparation of my olefin sulfides,

anemia 3 and, after substitution for the chlorine, have a tendency to split to re-form olefins. Though the thermally cracked olefin mixtures have this dis: advantage, they afforda convenient and economic source of raw materials .for the preparation of my improved olefin sulfides.

I may, with advantage, use as the olefin constituent, olefins or mixtures of olefins having from five to ten carbon atoms per molecule, whether they be produced by dehydrogenation, thermal or catalytic cracking or olefin polymerization. Higher molecular weight olefins may frequently be less desirable because of the lower proportion of active sulfur groups in the resultant addend. I

However, I prefer to use the more stable secondary olefins, for instance symmetrically disubstituted ethylene from which the more stable secondary chlorides may be formed by sulfo-- chlorination. Using these secondary olefins, the chlorine in the sulfo-chlorinated product may be more completely replaced by organic radicals and consequently there is less splitting out of the chlorine and resultant re-formation of the olefins. Secondary olefins, such as cyclohexane, octene-l, oleone and wax olefins, have been found to roduce stable inhibitors and may be used with particular advantage.

The sulfo-chlorination of thermally cracked naphtha has with advantage been effected by the following process:

In this operation there was used as the olefin constituent a thermally cracked naphtha boiling in the range of 200-300 F., and including the Cs and Ca fractions. This naphtha had an A. P. I. gravity of 56.4 and contained 48% by weight of olefins, as shown by the bromine number determination. There was charged to a flask, equipped with a stirrer and a cooling bath, 2333 grams of this naphtha, containing moles of olefin, and 675 grams (5 moles) of sulfur monochloride. 8201:, was slowly added over a period of 5% hours at a maximum temperature of 100 F. An addition rate of above 3 drops per second was found to cause excessive temperature rise and a loss of HCl. During this addition of the sulfur chloride, the mixture was stirred and the stirring was continued for 1% hours thereafter to complete the reaction. Following the completion of the reaction the product was washed to remove HCl and thereafter topped to a final bottom temperature of 210 F. at 30 mm. of mercury to remove the parafilns present. There was obtained from this operation 975 grams of a dark liquid product containing 23.1% sulfur and 12.9% chlorine.

Mercapto olefin disulfide was prepared from the sulfa-chlorinated olefin, produced as above described, by the following method:

A solution containing 400 cc. of 95% alcohol and 30 grams of NaOH (0.75 mole) was saturated with H128 to form an NaHS solution. 110 grams (0.31 mole) of the suite-chlorinated olefin was then added and the mixture refluxed for 7 hours and stored for 66 hours at room temperature. The reaction product was then dissolved in benzol and the benzol layer washed with water, dried and topped to remove the solvent. The resultant mercapto olefin disulfide was found by analysis to contain 26.8% sulfur and 0.88% chlorine.

Diamylamino olefin disulfide was successfully prepared as follows: A mixture of 150 c. c. benzene, 90 grams (0.25 mole) of the sulfo-chlorinated olefin, 157 grams (1 mole) of diamylamine, 30 grams (0.75 mole) of caustic soda and 150 c. c. of water were refluxed for 13 hours until the organic layer gave a negative Beilstein copper oxide test for chlorine. The organic layer was then separated from the aqueous layer. filtered and topped to remove excess amine solvent. By this operation, a residue of 87.2 grams was obtained.- This residue was filtered free of amine hydrochloride and was found by analysis to contain 20.85% sulfur, 1.66% nitrogen and 3.17% chlorine. The product was found to be readily soluble in lubricating oil fractions to an extent of at least 5%.

This analysis indicates that the substitution of amine for'chlorine had not gone to completion. Upon standing at room temperature, dechlorination continued, forming traces of oil insoluble amine hydrochloride. Though this product was useful in accordance with my present invention, it is desirable particularly in the preparation of olefin sulfides containing nitrogen for use in accordance with my present invention that all or substantially all of the chlorine be replaced by the amine.

Anilino olefin disulfide has been successfully prepared as follows:

227 grams (0.63 mole) of the sulfo-chlorinated olefin, 119 grams (1.28 moles) of aniline, 216 grams (4 moles) of sodium bicarbonate and 200 e. c. of toluenewere admixed and the mixture refiuxed for 14 hours at approximately 220 F. The organic layer thus obtained was at the end of this period found to be halogen-free. It was thereafter thoroughly washed with water and topped to remove the solvent toluene. By this operation, there was obtained 187 grams of the anilino olefin disulfide, equivalent to 63% of the theoretical yield. This material contained some oil insoluble crystals which appeared to be aniline hydrochloride, although, by analysis, the

halogen content of the mixture was found to be only .06%. These crystals were removed by diluting with naphtha, filtering and distilling the naphtha from the filtrate. This purified product was found to be soluble in oil at room temperature to an extent of 5% and to contain 2.31% nitron, 21.5% sulfur and 0.12% chlorine.

As the lubricating oil constituent of my improved lubricating oil compositions, various petroleum lubricating oil fractions may be used. For instance, solvent-treated Mid-Continent neutral or a blend of such neutrals with bright stock or a solvent-refined lubricating oil fraction from a Pennsylvania crude or various blends of such lubricating oil fractions may be employed. In the compounding of the lubricating oil composition of my present invention I have with advantage used a solvent-treated Mid-Continent 250 neutral refined by the so-called Chlorex process and having the following characteristics:

The proportion of the olefin sulfide addend used in the compounding of my improved lubricating oil composition may be varied somewhat but in my lubricating oil composition for the purpose of improving the film strength or imparting extreme pressure qualities to the lubricant.

The lubricating oil composition of my present invention may consist solely of the lubricating oil constituent, a calcium organic compound detergent and the olefin sulfide inhibitor. However, the addends 01' my present invention have been found to be compatible with other desirable lubri cating oil addends and the inclusion of such other addends is within the contemplation of my present invention.

The inclusion of said so-called calcium salt detergents, for instance, in internal combustion engine lubricants, has been previously proposed and been found highly advantageous. An especially efiective lubricating oil composition for the lubrication of internal combustion engines, and the like, contemplated by my present invention, is one comprising, in addition to the lubricating oil constituent and my olefin sulfide inhibitor, a minor proportion of the calcium salt of an octyl salic ylate, particularly iso-octyl salicylate or capryl salicylate. These calcium salts have been found particularly efiective as detergents in lubricating oil composition, as more fully described in the Willard L. Finley Patents Nos. 2,339,692 and 1 2,347,547 issued on January 18, 1944 and April 25,

' 1944, respectively.

The invention also contemplates lubricating oil composition containing my olefin sulfide inhibitor and other known calcium organic compound-detergents, for examplesuch as calcium cetyl phenolate, calcium petrolatum sulfonates, soaps and the like.

When used in conjunction with these detergents, particularly the calcium compounds such as previously mentioned, my olefin sulfide inhibitors and such detergents have been foundto complement each other so that the effectiveness of. each is promoted. The tendency of the detergent to promote oxidation of the oil and corrosion of bearing metal, at the termination of the oxidation induction period, is minimized by the presence of my olefin sulfide inhibitor without destroying the effectiveness of either the detergent or the inhibitor.

My improved lubricating oil composition will be further illustrated by the following specific examples in which thebase oil used was the solvent-treated Mid-Continent neutral previously described. The oxygen absorption rate of this base oil in the presence of copper-lead bearing metal was 25.6 cubic centimeters, at normal temperature and pressure, per minute per 100 grams of oil. This same base oil compounded with 1% by weight of calcium iso-octyl salicylate, previously referred to, had, in the absence of copperlead bearing metal, an oxygen absorption rate of 48.8 c. 0. per minute per 100 grams of oil and, in the presence of copper-lead bearing metal, an oxygen absorption rate of 50 c. e. per minute. The oxygen absorption rate of the base oil containing the calcium iso-octyl salicylate is that following the induction period of 167 minutes, in the absence of the bearing metal, and 107 minutes in the presence of the bearing metal.

The copper-lead bearing metal corrosion loss,

due to the uncompounded base oil, was 5.8 milligramsand the bearing metal corrosion loss occasioned by the base oil compounded with 1% of the calcium iso-octyl salicylate was 11 milligrams.

The advantages of my present invention, with respect to oxidation and corrosion characteristics of my improved lubricating oil compositions are illustrated by their mean oxygen absorption rates, as compared with the oxygen absorption rate of the base oil and the corrosion losses of bearing metals in contact with therespective lubricants.

Example 1 By the addition of 0.5% of the ,mercapto olefin disulfide, prepared as described herein, to the base oil, the oxygen absorption rate was decreased from 25.6 to l0.8, c. 0. per minut per 100 grams of oil. By the addition of the same amount or this olefin sulfide inhibitor to a blend of the base oil with 1% of the calcium iso-octyl salicylate, the oxygen absorption rate of the composition, in the absence of copper-lead bearing metal, was reduced from 48.8 to an average of 1.9 c. c. per minute. The oxygen absorption rate of this blend, in the presence of-copper-lead bearing metal, was reduced from c. c. to an average of 3.1 c. 0. per minute. The bearing corrosion loss occasioned by the compounding of 0.5% of the mercapto-olefin disulfide with the base oil alone was reduced from 5.8 to 0.6 milligram and,.where 1% of the calcium iso-octyl salicylate was also present, the bearing corrosion loss was entirely eliminated.

Example II disulfide to ablend of the base oil and 1% of calcium-iso-octyl salicylate, the oxygen absorption rate, in the absence of the bearing metal,

was found to average 2.5 c. c. per minute through out the test and, in the presence of the copperlead bearing metal, was reduced to an average of 2.9 c. e. per minute. When using the blend containing 1% of the calcium iso-octyl salicylate, the bearing corrosion loss was only 0.4 milligram.

Example III By the addition of 0.5% of diamylamino olefin disulfide, prepared as described herein, to the base oil, the oxygen absorption rate was reduced to an average of 7 c. 0. per minute. By the addition of 0.5% of the diamyl-amino olefin disulfide to a blend of the base oil with 1% calcium iso-octyl salicylate, the average oxygen absorption rate, in the absence of bearing metal,

was found to be 3.3 c. c. per minute. In the tests of the compounds thus prepared, the copper-lead bearing corrosion loss was completely In each instance the proportions of the addends used are based on the weight of the lubricating oil constituent. The tests of the base oils and of my improved lubricants of the foregoing examples were carried out under identical conditions. The oxygen absorption tests were carried out at a temperature of 360 F; and the results, in each instance, are reported as cubic centimeters of oxygen. measured under normal temperature and pressure conditions, absorbed per minute per 100 grams of the lubricant during the conventional oxygen absorption test.

Iclaim:

1. A lubricating oil composition comprising a major proportion of a petroleum lubricating oil fraction, a minor proportion of calcium iso-octyl salicylate, effective as a detergent, and a mercapto olefin disulfide in an amount sufiicient substantially to deactivate the calcium oi the detergent.

2. A lubricating oil composition comprising a major proportion of a petroleum lubricating oil fraction, a minor proportion 01' calcium iso-octyl salicylate, effective as a detergent, and an olefin sulfide in an amount suil'icient substantially to deactivate the calcium the calcium iso-octyl salicylate, said olefin sulfide being selected from the group consisting of mercapto olefin sulfides, diam'ylamino olefin sulfides and anilino olefin sulfides.

3. A lubricating oil composition comprising a major proportion of a petroleum lubricating oil iso-octyl salicylate.

FRANKLIN M. WATKINS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,230,966, Reid Feb. 4, 1941 2,282,710 Dietrich May 12, 1942 2,304,623 Berchet Dec. 8, 1942 2,347,547 Finley Apr. 25, 1944 2,361,043 McCleary Oct. 24, 1944 

